You probably just hexed it wrong.
They both work for me, Although i tend to use clean roms since i trust the M3 team to make their fixes correctly and also their fixes might fix M3 specific issues... Apperently this time this fix is a quite screwy...
But go ahead. Just make sure your firmware is v4.5Beta Touchpod or v1.42 Sakura.

MAKE A BACKUP OF EVERYTHING!!!

And avoid the following:

Deleting the .sav file and reloading the game after running it some time.

Not saving after running it for the first time.

This incident just made me lose my fate that i had in sakura to not spontanuesly self-destruct my SD card (At least on NDS roms, not homebrew), It made me even afraid to start any game, especielly Kingdom Hearts
In fear that it may give me those 2 black screens of death and corrupt my SD.
Now im taking backups from time to time so i wont lose all of my progress again -.-